checked = false;
function checkedAll() {
	 if (checked == false){checked = true}else{checked = false}
	for (var i = 0; i < document.getElementById('frm_emp').elements.length; i++) {
	  document.getElementById('frm_emp').elements[i].checked = checked;
	}
  }
  
function showClearAll() {
	var clear = document.getElementById('clear_all');
	if(clear.style.visibility=="" || clear.style.visibility=="hidden"){
		clear.style.visibility="visible";
	}else{
		clear.style.visibility="hidden";
	}
	return false;
}
